Primary care physicians' use of lumbar spine imaging tests: effects of guidelines and practice pattern feedback.

<bold>Objective: </bold>To reduce variability in primary care physicians' use of procedures for imaging the lumbar spine.<bold>Design: </bold>Controlled intervention using clinical practice guideline and practice pattern feedback.<bold>Study Sample: </bold>Sixty-seven internists and 28 family practitioners in a large, group-model HMO.<bold>Measurements and Main Results: </bold>Intervention group physicians received the clinical practice guideline for low back pain, followed after 4 months by three bimonthly feedback reports on their current use rates for lumber spine x-rays and computed tomography and magnetic resonance imaging scans of the lumbar spine. Control group physicians received neither the guideline nor the feedback reports. Automated radiology utilization data were used to compare intervention and control group physicians' changes in use rates and variability in use rates over the course of the study period. Neither the guideline alone nor the guideline plus feedback was associated with a significant decrease in use rates or in the variability in use rates for the lumbar spine imaging procedures under study.<bold>Conclusions: </bold>Clinical practice guidelines and practice pattern feedback fail to achieve their goals when features of the practice setting and patient expectations and behavior are not identified and addressed. [ABSTRACT FROM AUTHOR]